1. Field of the Invention
The present invention relates generally to processes and systems that use renewable biomass for generating power in the form of electricity and heat, for producing nitric acid-based fertilizer as a valuable by-product, and for accomplishing atmospheric remediation by sequestering carbon dioxide.
2. Description of the Related Art
The most prevalent form of electrical energy generation at this time in the United States is from fossil fuel systems. These include mainly coal and natural gas fired systems, as well as nuclear systems which account for about 15% of the market. While some progress is being made in making these systems more environmentally safe, they nonetheless produce large quantities of pollutants and toxic chemicals.
SO2 and NOx are in the form of gases that turn to liquids once they are vented and are the primary source of acid rain. The mechanisms to reduce these offensive and dangerous byproducts are expensive to build and take large amounts of energy from the plant to operate. The energy consumed in reducing these byproducts reduces the net electrical output of the generation plant, and thereby lowers the efficiency of a conventional plant into a range of 34 to 42%.
Conventional energy plants also generate high volumes (25 to 30% of fuel volume) of undesirable waste in the form of cinders and flyash which contains, among other things, arsenic, lead, cadmium, zinc, and mercury. As these materials exit the firebox, they carry along large amounts of heat, further reducing the efficiency of the plant. The fossil fuel systems are nonrenewable and consume fuels for which there are limited supplies.
While nuclear power generation produces minimal CO2 (primarily from electrical activity), decommissioning of nuclear power plants is expensive and inevitably leaves a contaminated site behind.
A well-known fact in the agricultural community is that grains are overproduced causing low commodity prices. The problem is too much grain and not enough uses and/or exports. Input costs continue to rise also causing losses to producers that have had to be subsidized by the government to stay viable. Fertilizer costs are the third highest input cost after land and machinery in grain production.
The most common fertilizers used today are nitric acid-based fertilizers. These fertilizers are typically produced by processes that use the gas phase oxidation of nitric oxide (NO) to nitric dioxide (NO2) and partially back to nitric oxide. However, such processes are considered relatively inefficient, expensive, and limited in their industrial applicability.
An improved process for recovering nitric acid (HNO3) from the NOx in a flue gas stream is described in U.S. Pat. No. 6,294,909 of Drinkard, Jr. This improved process involves reacting nitric acid with NOx to form N2O3 and water. The N2O3 reacts with water and is further oxidized to form additional nitric acid. Drinkard, Jr. has applied this technology to recover nitrogen gases from electric arc furnace dust in the steel industry. Drinkard, Jr. does not disclose the use of his NOx removal process in conjunction with a sustainable agricultural system that bums biomass to generate power, produce fertilizer, and sequester carbon.